Unity SkyBox Solution

I had the same problem many people where having here, using the Example Oculus Sky box solution and having it clip large terrain at a distance.

The solution is to use use a shader that is set to "Queue"="Background" and ZWrite off for the sky box materials.

Here is the shader I modified:

Shader "Unlit/Vertex Color Multiply Background" {

Properties {
    _Color ("Main Color", Color) = (1,1,1,1)
    _MainTex ("Texture", 2D) = "white" {}
}

Category {
	Tags { "Queue"="Background" }	
    ZWrite Off
    
    Lighting Off
    Fog {Mode Off}
    
    BindChannels {
        Bind "Color", color
        Bind "Vertex", vertex
        Bind "TexCoord", texcoord
    }
   
    SubShader {
        Pass { 
        
            SetTexture [_MainTex] {
                Combine texture
            }
            
            SetTexture [_MainTex] {
            	constantColor [_Color]
				combine previous * constant
            }
        }
    }
}
}

I use it by dragging the /Assets/Tuscany/Models/Prefabs/Skybox.prefab in to my scene, I replaced each material to use the above shader

I also created a script that makes the skybox copy my OVRCamera position but not its rotation:

using UnityEngine;
using System.Collections;

public class MatchPosition : MonoBehaviour {
	
	public Transform ParentPosition;
	// Use this for initialization
	void Start () {
	
	}
	
	// Update is called once per frame
	void Update () {
	if(ParentPosition !=null)
			this.transform.position = ParentPosition.position;
	}
}

So this way you can make the sky box small, encompassing both cameras and it will draw first before the entire scene without updating the zbuffer. Also i set both cameras Clear Flags property to Depth Only, since the background will clear the color buffer, you save a little bit of render time.